For Google Reader I can just do "Mark All As Read" and all unread articles are checked off.
I'd like to do the same for getpocket.com (formerly Read It Later) but I don't see a button or something for it.

I'm now scrolling past 200 articles, then bulk editing them, but with 3K items to go I'm thinking: there must be a faster way to do this.

4 Answers
4

Updated answer

Grab your scrollbar and drag it down. Since they have infinite scrolling now, you can load all items now. This will take some time if you have many items.

Shift-click the last items. All items between the first and last one will be selected as well

Hit Archive

Old answer

I wondered if this functionality was added in the mean time and checked my Pocket. As far as I understand your question, this does work now. (I don't know what happens, if you have like 3000 items – if there is a pagination, it may just work for the first page)

In the toolbar at the bottom – click the Bulk Edit icon (the first one)

To select all items, click the check box right above to label BULK EDIT

With the addon/extension 'Pick Pocket". Its not as simple as one click and done, but it is light speed compared to 3 click to delete on article. Get pick pocket, I swap to list view to load more files at once, then use the bulk edit, select all, action: delete, save changes (all located at the bottom) series of clicks to take out around 50 entries per routine.